给出程序的运行结果#include int main(){int a,b,c,d;char op1,op2,op3;int sum;printf("please input:a+b+c+d\n");scanf("%d%c%d%c%d%c%d",&a,&op1,&b,&op2,&c,&op3,&d);sum=a+b+c+d;printf("sum=%d",sum);return 0;}程序运行时从键盘输入:1<回车>2+3+1<回车>

A. sum=1
B. sum=6
C. sum=7
D. sum=3